Nelson also underlined that this motion [to proceed] is merely “to start debate on a bill and to try to improve it” — not a final vote to pass it.

“If you don’t like the bill, then why would you block your own opportunity to amend it?” Nelson said. “Why would you stop senators from doing the job they’re elected to do — debate, consider amendments, and take action on an issue affecting every American?”

I don’t know, Ben, why would a member stop senators from doing the job they’re elected to do?

Nelson said in a statement that he “cannot support proceeding on a bill I haven’t seen.” But that’s silly — Sen. Chris Dodd (D-Conn.) published a draft more than a month ago, and released the official legislative language 10 days ago.

Of course, it’s not exactly a mystery as to why Ben Nelson sided with Republicans to prevent a debate on Wall Street reform. The Democratic bill includes tough new restrictions on derivatives, and Warren Buffet, a billionaire Nebraskan, has tens of billions of dollars in derivatives contracts. Buffet, not surprisingly, has been urging Nelson to help protect his business, and the senator seems inclined to do what his wealthiest constituent wants.

Over the weekend, Nelson sought a special side deal (yes, again) that would have created an exemption, shielding existing derivatives from new regulations, and in the process relieving Buffet of any new burdens. Dodd thought this was absurd, rejected Nelson’s plea, and apparently pushed Nelson into blocking a debate.

Note the shift in Democratic strategy, as compared to last fall: Dems are so confident Republicans will eventually come around on Wall Street reform, they don’t feel the need to give in to Ben Nelson’s ridiculous demands. With health care, Dems had no other options.